Magnus I would say that yes I do have various backups and none as good as any of this discussion. Agreeing with Jim much of this appears to me to be semi-reasonable and in particular in a amateur lab environment. But I am afraid thats just about how far I am going to get on the project. Its right behind the H maser. Any day now. Recovering the Frankenstein CS was about my real limit. I haven't seen any tubes show up on ebay lately. :-) Such is life. Regards Paul WB8TSL
On Sat, Nov 1, 2014 at 12:49 PM, Jim Lux <jim...@earthlink.net> wrote: > On 11/1/14, 9:08 AM, Magnus Danielson wrote: > >> Paul, >> >> You mean, as all time-nuts already have redundant sites with at least 4 >> 5071As with high-performance tubes, redundant cesium and rubidium >> fointains, set of active hydrogen masers, with everything in tight >> temperature, humidity and pressure control, UPS and diesel-engines, >> GPS/GLONASS/GALILEO receiver on temperature-stabilized piller and >> antenna, do TWSTFT to major labs... since money is no issue, right? >> >> The main problem with cesium tubes as I recall it is really the ionizer >> in the mass-spectrometer being poluted with cesium, this then creates >> bad S/N before running out of cesium in the oven. >> >> Yes, I agree it would be a great clock to have, but practical limits in >> cost is a challenge for most, so it would be interesting to look at it >> and ask how cheap it could be done. >> >> >> > > Having been to a few of the design reviews and such for the DSAC, and > before, when it was called the 1 liter atomic clock, etc. > > I think one could build one *if* you have a fairly wide collection of > skills, and you weren't hung up on it being tiny and low power, and zero > maintenance. > > For instance, building a perfectly sealed physics package that is space > flight compatible is non-trivial. Most of us don't have e-beam welding > equipment sitting around (nor does JPL.. we contract that kind of stuff > out). As Prestage points out in the article below, they started looking at > how they build long life Traveling Wave Tubes for space (another precision > ion optics device), and having spent some time in various TWT factories > over the past 15 years: there is a lot of art in the manufacturing process. > > http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/41329/1/07-2003.pdf > http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/41395/1/08-0610.pdf > > However, if you were happy with "lab grade" construction, and you have the > Kurt Lesker and Duniway catalogs as bedside reading, I think you'd have a > chance. > > The ion trap and such is a fairly straightforward thing, from what I > understand: you need the usual vacuum pumps and such to build one. If you > don't want it to run for years without servicing, then issues of the > mercury content are less important. > (BTW, the space clock uses thermal dissociation of HgO to get the mercury) > > The PMT is an off the shelf thing. Check out the amateur built fusion > reactor (fusor) websites on where to get PMTs and amplifiers (they're used > behind a scintillator) > > The 40 GHz stuff these days is not nearly as exotic as it used to be. The > challenge might be test equipment when you're debugging your 40 GHz > synthesis chain. > > > > I don't think it would be *easy*, but I think doable, and nothing in the > system is particularly expensive or that exotic. It's sort of like > telescope building.. The raw materials to make a 18" reflector telescope > aren't all that expensive, nor is there some secret sauce: it's just time > to grind the mirror (and recover from mistakes) and build the system. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.